#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>
int js(char *ch)
{
	char s[80];
	int len = strlen(ch);
	int i = 0;
	int j = 0;
	int z = 0;
	for (i = 0; i < (len-1)/2; i++)
	{
		s[j++] = ch[i];
	}
	int y = j;
	j = 0;
	for (i = len-1; i > y; i--)
	{
		if (s[j] == ch[i])
		{
			z++;
		}
		j++;
	}
	if (z == (len - 1) / 2)
		return 1;
	else
		return 0;
}
int main()
{
	char ch[80];
	gets(ch);
	int x = js(ch);
	if (x)
	{
		printf("YES\n");
	}
	else
		printf("NO\n");
	return 0;
}